Dash-pot accelerating device.



3 SHEETSSHEET I.

fill/IA Patented Nov. 9, 1915.

COLUMBIA PLANOGRAPH C0.. WASHINGTON, D. c

D. LARSON.

DASH POT ACCELERATING DEVICE.

APPLICATION FILED 050.22. 1908.

Patented Nov. 9, 1915.

3 SHEETS-SHEET 2.

COLUMBIA PLANOIJRAPH c0. WASHINGTON. D. CI

' UNIT D sT rEs arana o EroE.

DAVID LARSON, OE YoNK s, nEw YORK, assIcNoR T0 ocrrs ELEVATOR coMPAivY, OE

'- JERS Y CITY, NE JERSEY, A CORPORATION E NEW JERSEY.

nAsE-ro'r ACCELERATING DEVICE.

To all whom it may concern. I Be it'known that 1, DAVID LARSON, a subject of the King of Sweden, residing at Yonkers, in the county of lVestchester and State of New York, have invented a new and useful Improvement in Dash-Pot Accelerating Devices, of which thefollowing is a specification. 1 a r 7 My invention relates to an improved dashpot accelerating'device, especially designed for use in connection with an electromagnet, and more particularly described inthe pres ent embodiment as applied to an electromagnetic device for automatically accelerating an electric motor.

One of the objects of the invention is to provide a dash-pot accelerating devicewhich shall be practicallyindependent of the voltage applied to the magnet winding terminals.

Another object is to provide an accelerat ing'device in which the entire time for accelerating is practically constant. I

A still further object is to provide a simple, durable and inexpensive device for accelerating a motor which is positive in action, eifectiveand efficient in operation.

For the attainment of theseends and the accomplishment of other new and useful ob-. jects, the invention consists in the features of novelty in the construction, combination and arrangement of the several parts hereinafter more completely described and claimed inthe appended claims.

In the accompanying drawings, Figure 1 is a side view partly insection, showing my improved" dash-pot accelerating device in conjunction with an accelerating magnet; Fig. 2 is a detail view of the same after the dash-pot plunger has descended, thereby making connection with a fixed contact; Fig. 3 is a detail sectional view of the dash-pot and plunger construction; Fig. 1 is a front view of an accelerating magnet to which my invention is applied, also showing details of constructionand arrangement in dotted outlines; Fig. 5' is a top view of the same; and Fig. 6 illustrates the embodiment of-my invention used in connection with another accelerating magnet to control the acceleration of an alternating current motor.

The magnet frame 11 is suitably mounted upon or secured to the base orswitchboard 12 by the bolts 13. The magnet lever 14; is

pivotally mounted-upon the magnet frame Specification of Letters Patent.

a pin 29.

Patented Nov. 9, 1915.

- Application filed. December 22, 1908. Serial No. 468,837.

11,--and normally swings downward on the p vot pins-22 to take the position shown in Fig. 1 when the magnet is not energized.

The magnet winding 16 is secured to the magnet frame 11 and the laminated iron core 17, also securedto the magnet frame 11, extends part way through the magnet windmg 16. Secured tothe magnet lever 14 is the laminated iron core 18, and when the magnet is energized to draw up the magnet lever 14:, the core 18 is moved inward within the magnet winding 16 and meets or nearly meets the other laminated core 17.

dash-pot 19, opening downward, and in this dash-pot 19 the plunger 20 is adapted to slide. 7 Attached to the'plunger. 20 by the pin 21 is the link 24 having a reduced portion 26 through which'the pin 21 passes, and permitting a slight swinging. motion of the link 24 about the said pin 21. This link 24 is provided with a rectangular opening and alined holes 27 on opposite sides of this rectangular opening are adapted to receive Secured to the magnet lever 14: by the stud I 7 bolt 30 and the nut 31 is the lever arm 15,

having the extremity 32 so shaped as to enter the opening 25 in the link 24. The pin 29 secured in the holes 27 in the link 24: also passes through the slot 33 in the extremity 32 of the lever arm 15, whereby the latter is held in connection with the link 24. A shoulder 34 is provided 011 the lever arm 15 V which engages on the edge of the opening 25 when the magnet lever 1a is drawn up.

The dash-pot 19 is provided with two openingsfor admitting and discharging air; One of these is the threaded hole 35 in which the threaded bolt 42 fits. This bolt 42 is provided with a longitudinal beveled slot 11, by means of which the amount of opening to the dash-pot 1.9 maybe accurately gaged by manipulating the bolt 42, thus allowing the plunger 20 to fall more rapidly as the opening is increased.- The other opening to the dash-pot 19 is provided with a check valve which permits the discharge of air from the dash-pot 19' and prevents the admission of air thereto: This opening 38 hasa smaller opening 36 communicating with the dash-- pct 19, and also a smaller lateral opening 40, the top of the opening 38 being stopped up with the screw plug 39. In the bottom of the opening 38 is a ball 37 covering the smaller opening 36, and acting as a trap or check valve in the well known way permitting the discharge of air from the dash-pot 19 and preventing admission of the same through the hole 36. The plu 39 is for the purpose of keeping the ball 37 in the opening 38.

An electrical contact 16 is supported by the holder %7 which extends through the switchboard 12, and has a threaded portion 1-3 upon which are the lock nuts 44. These look nuts serve the double purpose of securely fastening the holder 17 to the switchboard, and holding the terminal in electrical connection with the said holder. When the link 2 falls or descends, it strikes this fixed contact 16, making electrical connection from the terminal 15 through the holder l7, contact 46, link 2 1, lever arm 15, nut 31, to the terminal 49 which is held by the lock nut 28 in connection with the nut 31.

The magnet frame 11 is formed with a vertical flange or extension 11 provided with openings in which the contact rods 50 are adapted to slide. Each contact rod is provided with a contact head 51 at one end, and the other end is threaded to receive the lock nuts 55. The threaded ends of the rods pass through openings 59 in the lugs 54 on the magnet lever 14, and these lugs 54 engage the lock nuts 55, causing the contact rods 50 to be moved with the armature lever 14: when the magnet is deenergized (Fig. 1). Coil springs 52 suitably placed about projections 53 formed on the flange 11 act against the heads 51 of the contact rods 50, tending to force these heads into contact with the fixed contacts A bu'lfer device 62, preferably formed of rubber or other soft material, is secured to the armature lever 14; in position to limit the inward movement of the armature by engaging an adjustable bolt threaded into the flange 11 and locked in position by a lock nut 61.

Conductors 57, to which are secured the lugs 56, are held by lock nuts 55 in connection with the contact rods 50. These conductors 57 preferably pass through the switchboard 12, and are connected to terminals 64.- by lock nuts 63 which secure said conductors and terminals to the switchboard in the well known manner. The fixed contacts 58 are secured in the holders 66 by the bolts 65. The holders 66 are formed with studs 67 which project through the switchboard 12 and are screwthreaded to receive the lock nuts 68 which secure the contact holders in position and also form a convenient means for holding the terminal clips 69 and electrically connecting them to the contacts 58.

When the magnet is in its open position (Fig. 1). and a circuit is closed to the magnet winding 16 through the leads 70 and 71, the magnet lever 14: is attracted and tends to move inward to close the air gap between the laminated cores 17 and 18. Rapid response to this energization is prevented by the action of the dash-pot 19. The leve arm 15 is rigidly attached to the magnet lever 14 and the shoulder 34: on the same arm is in contact with the link 2 1 attached to the plunger 20, so that the inward pull on the armature lever causes a downward pull on the link 2& and plunger 20. Air is admitted slowly to the dash-pot chamber 19 through the beveled slot 11 in the screw 42, and in consequence the plunger 20 moves downward as slowly as desired. under the pull of the lever arm 15. "When, however, the plunger 20 and link 241- have moved down a sufficient distance, permitting a corresponding movement of the lever arm 15, and when the contact 51 is within a short distan :e of the contact 58, the shoulder slips off of the link 2d and permits a quick engagement of the contact 51 with the stationary contact 58. During this final movement of the contact 51 the beveled portion 70 of the lever arm 15 slips along the link 2+, the slot-andpin connection between the lever and link permitting this movement. By the time the contact 51 engages the contact 58, the slot has moved part way down along the pin 29 and this relative movement of the slot and pin is quickly completed during the initial compression of the spring 52. The upper end of the slot is now against the pin so that the dashpot is again effective to retard the final movement of the armature. The link 24 and plunger 20 will continue to drop slowly until the link 2% makes contact with the fixed contact 46, and then an electrical path will be completed from. the terminal. clip 45, through the holder -17, contact l6, link 24, and arm 15 to the clip l9. t will thus be seen that the dashpot acts to retard the armature 11 during the initial portion of its movement, that is, up to the point where the shoulder 34 is released, permitting a quick travel of the armature, until the pin 29 engages the upper end of the slot 33, when the dashpot again retards the armature during its final movement.

When the magnet is deenergized, the lever arm 14: falls back quickly until the pin 29 engages the slotted opening 33 in the extremity 32 of the lever arm 15. Then the weight of the magnet lever 14: acting about the pivot 22 presses up on the plunger 20 by means of the lever arm 15. The air is expelled from the dash-pot 19 through the admission slot 11 and also through the opening 36, which latter is also sufficiently re stricted to exert a certain retarding effect. Thus the dash-pot 19 and plunger 20 prevent the dangers incident to a complete sudden release of the magnet lever with nothing to retard it in its movement to open position.

noids 73 and 73.

starting of the same.

operation of the switch K and the solenoids 71, 73, 78 in'connection therewith, and the acceleration of the motor is effected by means of the magnets A and B in connection with'the resistance R. Only the magnet A is provided with my dash-pot accelerating device, as only one of the dash-pot devices is necessary for every two magnets.

When the switch Sis closed to the "supply mains, the operation of the hand lever 80 of the control switch K in one direction causes first the energization of solenoid 71 and then one or the other of the reversing switch sole- VVhenthe contact 80 of thehand lever 80 makes connection between the contacts 83, 82, 81, a circuit is first closed from the main 100, through wire 102, contacts 81, 80, 83, wires 72, 103, solenoid 71, and wire 117 to' the main 101, thus energizing the solenoid 71. This attracts and raises the core 74 to which is attached the rod 77 and the contact bar 85. The contacts 88 and 90 on this contact bar 85 make con nections with the contacts 84 and 89, respectively. The solenoid 7 3 is now energized by a current from main 100, through wire 102, contacts 81,80, 82, wire 105,.solenoid 73, wires 120,121, 118, contacts 84, 88, to main 101. The energizing of this solenoid 78 attracts the core 76, thereby raising the core and rod 79, to which the contact bar 87 and the contacts 96, 98 are secured. These contacts 96, 98 make connections with the fixed contacts 95, 97, respectively. The operation of these last named movable contacts 96, 98 close circuits to the motor M to effect the The paths from the switch S to the motor may be traced: .(1) from the switch directly to the motor through the main 100; (2) from the switch, wire 101, contacts 88, 84, wire 118, contacts 97, 98, wire 104 to thernotor M; from the switch, through wire 99, contacts 90, 89, wire 119, contacts 95, 96, wire 102 to the motor. If the hand lever 80 is thrown in the other direction to make connections be tween the contacts 81, 82, 83 the solenoid 7 3 will be energized and the wires 99, 101 would be connected with wires 104, 102, respectively, instead of with 102, 104, respec tively, and the direction of rotation of the motorwould be reversed.

Acceleration of the motor is accomplished by varying the resistance in circuit with the secondary winding of the motor. The resistance R is of the three-phase type,-having three branches a, I), c uniting at a common point 122,- and each branch is provided with taps at intermediate points for efl'ecting a gradual variation of the resistance in the secondary circuits. These taps are connected with contacts on the accelerating magnets A and B. As soon as the main circuits to the motor are closed through the wires 102,

100, 104, the magnet A is energized, the cir-' cuit therefor being from wire 100, through wire 122, magnet winding 16, wire 123, contacts 124, 124, wires 125, 126, to wire 104. This magnet A is provided with the dashpot device which prevents the instantaneous drawing up of the magnet lever 14, in the manner previously described. When the magnet lever 14 is drawn up, connection is made between the contacts 129, 130, 181, thereby short-circuiting the portions of the resistance R between the taps a, b, 0, and. the common point 122, thus reducing the resistancein the circuits of the secondary windings. When the action of the dash-pot 19 allows the contacts 24 and 46 to connect,

a circuit is closed by such connection through the winding 127 of the magnet B that is, from motor lead 100, through wires 122, 184, magnet winding 127, wires 132, 135, contacts 46, 24, wires 136, 126, to the w1rc 104. Energizing, the magnet B operates the magnet lever 137 thereof, and connections are thereby made between contacts'129, 130, 181, and between contacts 124 and 128. The contacts 129, 130, 131 are connected directly to the wires 106, 105, 107, respectively, and the secondary windings of the motor are short-circuited" when the said. contacts are connected together. The movement of the armature lever137 toward its magnet brings the contact 124 into engagement with the contact 128, and simultaneously or immediately after separates the contacts 124 and 124. The engagement of the contacts 124 and 128 closes a local circuit across the contacts 24, 46 by way of the wires 133, 125, so

, the magnet coil 16, so thatthe magnet A is restored to its initial condition and current 15 only requiredtor the magnet coil 127 From this described construction and operation of thedash-Pot accelerating device, it is evident that the action of the mag.

net lever may be governed by the dash-pot bymeans of its air admission and escape openings, and the action of the magnet lever is also practically independent of the voltage applied to the magnet, so long as there is sufficient current to properly energize the magnet, through the magnet winding, to

, operate the magnet lever. Furthermore, the contact linkof the dash-pot plunger Wlll fall in practically the same time each time it falls, since the air is admitted to the dashpot through a small fixed opening, and therefore the contact completing an energiz ing circuit to the other magnet will be made in practically the same time after the first magnet is energized, no matter what the impressed voltage may be, so long as it is suiiicient. Thus the time for complete o-peration of a magnet thus equipped is practiailly constant for any single position of the air opening. l Vith this arrangement it is evident that only one of the dash-pot accelerating devices is necessary for two accelerating magnets, as it is impossible to operate the magnets more rapidly than they are set for. The accidents incident to the too rapid acceleration of a motor are thus obviated.

The present invention is not limited to the use of a single pair of controlling magnets it and B, as any desired number may be used and connected to operate successively to secure any desired degree of refinement in the control of the motor. For the sake of simplicity, the illustration has been limited to a single pair of these magnets.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Vi hat I claim and desire to secure by Letters Patent is 1. The combination of a magnet comprising a movable member, a pneumatic retarding device, and mechanism connecting said retarding device with the movable member and retarding the latter during the initial and final portions of its movement and permitting said member to move independently of the retarding device during an interme diate portion of its movement.

2. The combination of an electromagnet and its armature, a dashpot, a lost motion connection between said armature and dashpot for allowing a relative movement therehetween, and an additional connection between said armature and dashpot operative only during the initial movement of said armature.

3:3. The combination of an electromagnet and its armati'ire, a pneumatically controlled retarding device, and mechanism forming a connection between the armature and retarding device preventing independent movement of said device and armature during the initial and final portion of their movement and permitting such independent movement when the armature is in an intermediate position.

i. The combination with a magnet frame, of a magnet winding, an armature lever movable toward the magnet frame when. the magnet is energized, a dash-not in the mag net tl'ra'me. an arm attached to the armature lever, and means forming a connection between the said arm and the dash-pot for timing the complete movement of the armature lever in one direction.

The combination with a magnet frame, of a magnet winding, a pivoted armature lever, an arm rigidly attached thereto, a dash-pot, a plunger therefor, and a link pivotally attached to the plunger and having a lost motion connection. with said arm for controlling the speed of motion of the mag net lever only during its initial and final movements.

6. The combination with a magnet frame, of a magnet winding, an armature lever piv otcd to said frame, an arm rigidly attached thereto, a dash-pot, a plunger therefor, and a link pivota'lly attached to the plunger and having a lost motion connection with said arm for automatically timing the operation oi the lever only during its initial and linal movements in one direction 7. The combination with a magnet, ot' a magnet lever adapted to be attracted by the magnet, a dashpot, a. plunger therefor. an arm attached to the magnet lever, a shoulder on said arm, a link pivoted to the plunger and engaging said shoulder and means ofli'ected automatically by the movement of said arm to withdraw the shoulder on the arm from engagement with the link and. thereby permit a relative movement between said arm and link lior the purpose set. forth.

8. The combination with a magnet, ot' a magnet lever adapted to be attracted by the magnc. a dash-pot and plunger, means as sociated with the dash-pot and plunger for engaging the said lever and retarding its initial nn vemcnt, and means for suddenly releasing the lever from the said engagement and permitting a quick intermediate movement of the lever and again applying the dashpot retardation to the lever during its final movement.

9. The combination with a. magnet, of a magnet lever movable into attracted position, a contact movable by the magnet lever. a. cooperating fixed contact, a plunger and dashpot, a connecting mechanism between the magnet lever and the plunger and dashpot to apply the retarding action of the dashpot to the magnet lever during the initial movement of the armature toward closed position, a lost motion device in. said connecting mechanism to permit the magnet lever to move independently of the dashpot and plunger just before the movable contact makes connection with the fixed contact, and again apply the retarding action of the dashpot to the magnet at'ter connection has been made between said contacts.

10. The combination of a magnet comprising a. movable member, a stationary switch contact, a coiiperating switch contact movable with said member into engagement with the fixed contact when the said member is in an intermediate position, a retarding device, and mechanism connecting said retarding device to said movable member and retarding the movement of the latter during the initial and intermediate portions of its movement, but permitting a quick final movement of the said movable switch contact independently of the retarding device.

. 11. The combination with a magnet, of an armature moved when the magnet is energized, a dash-pot and plunger, a link at tached to the plunger, a fixed contact in the path of movement of the said link, and opcrating connections between the link and I with the fixed contact when the magnet armature.

12. The combination with a magnet, of an armature lever movable toward and from the magnet, a fixed contact, a movablecontact rod and contact held out of engagement lever is in open position, means for moving the movable contact into engagement with the fixed contact when the lever is operated, a dash-pot and plunger operative to retard the action of the lever, a link connection between the plunger and armature lever, and means for completing an electric circuit through the said link after the said contacts have been brought into engagement.

18. In an accelerating'magnet, the combination witha fixed member, of a movable member adapted to be attracted to the fixed member when the magnet is energized,- a fixed contact, a movable contact rod and contact held out of engagement with the fixed contact when the magnet is not ener- I the two contacts.

, the armature permitting a quick movement gized, a spring tending to join the two contacts, a dash-pot located in one of the said members, a plunger therefor, a connection comprising a link between the plunger and the movable member, and" means for coi pleting an electric circuit through the linkafter the said spring has operated to join 14. The combination with a magnet and its armature, of means for retarding the Copies of this patent may beobtained for of the armature when in an intermediate position.

17. The combination with an electromagnet and a movable armature therefor, of a retarding device, a lost motion connection between said device and the armature, and an additional connection between the retarding device and armature effective only during the initial movement of the armature toward its magnet.

18. The combination with an electromagnet and an armature movable toward and from the magnet, of a mechanical device for retarding the movement of the armature, switch contacts held apart while the armature is in its open position and movable into engagement when the armature reaches an intermediate position, and additional switch contacts held apart by saidarmature and movable into engagement when the armature is at or near its retracted position.

19. lhe combination with an electromagnet and its armature, of switch contacts held apart by the armature while in open position, means for moving said contacts into engagement when the armature reaches an intermediate position, additional switch contacts, and connections between the armature and one of said contacts operative to move the latter into engagement with the other of said a dditional'contacts when the armature is moved to its attracted position.

20. The combination with an electromagnet and an armature therefor movable toward and from the magnet, of a dash-pot, a connection between the dash-pot and the armature, a switch held open by the armature when the latter is in open position, means for closing the switch when the armature reaches an intermediate position, an

additional switch,and mechanical connec-v tions between the armature and said additionalswitch for closing the latter after the first named switch is closed.

21. The comblnation with an electromagnet, of a pivoted armature lever, a dashname to this specification in the presence of two subscribing witnesses.

, DAVID LARSON. Witnesses:

H. BHMARSDEN, ROGER W. FLAGG.

five cents each, by addressing the Commissioner of llatents, Washington, D. G. 

